Hydraulic shock absorber



Aug. 6, 1946. v H s A 2,405,502

HYDRAULIC SHOCK-ABSORBER Filed June 16, 1944 5 Sheets-Shet 1 Aug. 6, 1946. F. R. HAR RI S 2,405,502 HYDRAULIC SHOCK-ABSORBER: 1

Filed June 16, 1944 5 Sheets-Sheet 2 Q Q @IJDIJIJUDHU uu@ Q@ Q Q uuuqpunu if INVENTOR. 54

FffdPF/(R Harris 7 72mm QJM Aug. 1946. F. R. HARRIS 9 HYDRAULIC SHOCK-ABSORBER Filed June 16, 1944 5 Sheets-Sheet 3 l INVENTOR.

Frderzk 1?. l1 arm's Aug. 3, 1946.

F. R. HARRIs' 2,405,502

HYDRAULIC SHOCK-ABSORBER Filed June 16, 1944. 5 Sheets-Sheet 4 Frw/mb 1?. lfarm's 1 @Ma ev/W ezgo 6, 1%. F. R HARRIS 2,45,

. HYDRAULIC SHOCK-ABSORBER v Filed June 16, 1944- 5 Sheets-Sheeti I V EN TOR. Prev/0rd Rfimwl; I B Y Patented Aug. 6, 1946 UNITED STATES PATENT OFFKIE.

15 Claims.

This invention relates to improvements in shock absorbers; and more particularly shock absorbers for mounting upon floating drydocks to facilitate the raising of ships therein.

In my application for patent on a shock-absorbing floating dry dock, Serial No. 487,735, filed May 20, 1943, which issued as Patent No. 2,390,300 on December 4, 1945, I have set forth the usefulness of shock-absorbing equipment for cushioning a ship as the dock lifts it out of the water. and thus preventing serious collisions betwen the floor of the dock and the bottom of the ship. In such operations, a shock-absorber incorporating hydraulic principles'has marked advantages; and the chief object of this invention is to provide a hydraulic shock-absorber suitable in design for such a, purpose.

Another object of the invention is to provide a shock-absorber of the hydraulic type which is built to utilize the water that floats the dock as the cushioning medium, is simple in construction but strong and durable, resistant to damage, and ca able of giving the desired cushioning effeet for long periods of service.

A further object of the invention is to provide efficient shock-absorbing equipment suitable for both the bottom or floor of the dock and the side walls thereof; so that both the bottom and the sides of a vessel in the dock are protected against damage.

In the following description I have set forth one or more embodiments of the invention; but I do not wish to be necessarily limited to the precise structural details thereof. In practice, many changes can be made without'deviating from the essential character of the invention or exceeding its scope.

On the drawings, which are a part of the disclosure herein:

Figure 1 is a top view of a hydraulic shockabsorber according to this invention, intended for the sides of a, floating dock.

Figure 2 is a section on line 2-2 of Figure 1.

Figure 3 is a similar section, showing the parts in a different position.

Figure 4 is an end view of part of a dock and Figure 5 is a top view showing how such a shockabsorber is mounted in operative position.

Figure 6 is a section on line 6-6 of Figure 2.

Figure 7 is a section on line l'! of Figure 2.

Figure 8 is a section on line 88 of Figure showing a shock-absorber for the deck or floor of afioating dock.

Figure 9 is a section on line 9-9 of Figure 8.

Figure 10 is a top view of the same shockabsorber, broken away at one side, to illustrate the inside construction.

Figure 11 is a vertical section on line I |l l of Figure 10.

Figure 12 is an enlarged section on line 12-12 of Figure 10.

Figure 13 shows in section on line |3--l3 of Figure 14 another form of base or pedestal for the shock-absorber, to be mounted at the middle of the floor of the dock in line with the keel blocks.

Figure 14 is a horizontal section on line [4-14 of Figure 13. I

Figure 15 is a top plan of a base for a shockabsorber adapted to be mounted in line with the bilge blocks.

Figure 16 is a front view on line l6! 6 of Figure 15 of the base shown in Figure 15.

Figure 17 is a vertical section on line "-41 of Figure 15.

Figure 18 is a horizontal section on line l8--l8 of Figure 19.

Figure 19 is a side view of another design of a base or pedestal for shock-absorbers under the keel of a'ship.

Figure 20 is a View of the base seen from the right of Figure 19; and

Figure 21 shows a detail.

The same numerals identify the same parts throughout.

The pontoon hull of a floating dry dock is shown at l in Figures 4 and 5, with the side or wing walls 2. The deck or floor of the dock may have the usual extension or outrigger 3 at each end. The keel blocks 4 are shown near the middle of the floor, and. at the sides of the floor near the ends are rows of similar blocks 4a usually called bilge blocks. Near the ends of the floor, in line with the keel blocks are shock-absorbers 5, and additional shock-absorbers of the same construction are placed in suitable numbers along the sides of the fioor between the inner ends of the rows of bilge blocks 4a. On the inner or inboard faces of the walls 2 abut halfway between the floor of the hull and the top are the side wall shock-absorbers 6, in a row extending the entire length of the dock. I shall describe the latter first, referring to Figures 1, 2, 3, 6 and 7.

The side wall shock-absorber includes a plunger or piston 7 in a cylinder or casing 8. Attached to the plunger are hollow posts 9 which project from the cylinder 8 and carry at their outer ends a head 10 having a thick covering of rubber or some other resilient material II. The cylinder 8 has a movable cover 'plate l2, with openings through which the posts or legs 9 pass freely, and this plate can slide in any direction across the open end of the casing 8. Between the plate 12 and head Hi, the posts 9 are encircled by helical springs III which normally force the head i outward to the position shown in broken line in Figure 2, so that the plunger 7 is held near to the outer end of the cylinder 8. When the dock is submerged and a ship is moved into it, the easings 8 all fill with water; and ii the dock and the 'ship should lurch or swing, so that the hull moves close to either side 2 as the dock is raised, the

impact is deadened by the combined effect of the water in the cylinder and the spring i3.

The cylinders 3 are secured to the clock by beam l4 affixed to the outside of these casings and running from end to end thereof. Adjacent the upper and lower sides of the cylinders in position on the walls 2, the beams l4 are affixed at the bases of the cylinders to horizontal beams I5. Each lower beam I5 rest at the end-s upon reinforced iron wedges i6 welded thereto and to the side walls 2,,and the upper beams {5 are aflixed at their ends to reinforced spacers ll of greater height, and with inclined lower faces, so the ends of the cylinders are in vertical planes and the posts 9 may be horizontal. The bottom of each cylinder is braced bycrossed T-beams l8, vertical andhorizontal, the ends of vertical beam 18 being joined to the inner ends of beams or ribs [4, web to web and flange to flange; and in line with the webs of the vertical beams 18 and beyond the adjacent beams I4 are stiffening plates I9,between' the ends of the beams J4 and the webs of the beams 15., The beams 18 are all of course in pieces, joined at the pointsof inter section so that they are all in the same plane. The piece 'are-welded together and to the bottoms of the cylinders, and welding can be utilized wherever else it is needed to secure any of the parts together. The horizontal beams 18 are made fast to the ribs or beams M at the sides of the cylinders, 8; and the latter beams [4 are made fast at their ends near the bottoms of the cylinders to vertical channel beams 20 which are welded web to web and flange to flange to the beams IS; the web of the channel beams being extended to make junction with the Webs of the beams at 2 l. Stifiener plates !9 are also placed between the flanges of the beams adjacent the beams R4 at the sides of the cylinders welded in place. The whole assemblage of each cylinder is thus strongly made and strongly mounted in place on the side wall 2. g

The plungers I for the cylinders comprise back plates 22 with thick rims 23, consisting of rings welded to the circumferential edges of the plates. The inner ends of the hollow posts 9 are welded to the plates, and braced by ribs or webs 24 connecting the post to one another and to the rim 23. The cylinders 8 all have outward extending rim 25. To these rims are bolted annular plates 26 having radial ribs 21 on their outer faces to engage the cover plates 12. The latter have strengthening rim 28, joined by dia'metral stiffening ribs 29. In each of the quadrant thus formed each cover plate I2 has an opening 30 for one of the posts 9,'and over each opening is a flat covering rings 3|, surrounding the post 9. A similar ring 32 surrounds each post'at the head l0, and the spring I3 abut the rings 3| and 32. The plungers can therefore tilt in the cylinders as indicated in Figure 3, making the closure plates l2 slide on the ribs 21, and causing some movement of the rings 3! from side to side on. the

plates l2 without uncovering the outer ends of the cylinders 8. As the dock is sunk, water can enter and escape from the cylinder by way of the space between the plates 26 and closures I2.

The heads l0 have perforated rims 33 surrounding the posts 9, and the rim is braced by diametral rib 34. The springs I3 force the heads i8 outward, and as the dock is sunk, the cylinders 8 fill with water flowing in between the plates 12 and 26; these two plates being separated to a suificient extent to let water flow between them, and if the side of the ship should collide with either wall 2, the impact is taken up by the cushions H, springs I3 and the water in the cylinders, which may in part be forced out by the plungers i. To this end the plunger I fit somewhat loosely in the cylinders 8, the diameter of these plungers being somewhat less than the inside diameter of said cylinders. Hence, damage is averted. The pistons I can tilt in the cylinders 8, and these shock-absorbers are effective at various angles or" impact.

The hydraulic shock-absorbers 5 for the bottom of the dock comprise base made of crossed I-beams 35, in pieces or sections, welded flange t0 flange and web to web, and supporting on their outer ends upright I-beams or columns 36, four on each base and inclined slightly outward. At thetops of these pedestals thu built are heads 3'! or fixed pistons, the tops of which are thus mounted at a level slightly below the tops of the blocks 4 and 4a, surrounded by hollow annular floats'or movable cylinders 38. On the top of each float, surrounding the inner edge, is a buf fer or cushion ring 39,01? rubber or any other suitable material. At the bottoms these floats have stops 4!! projecting beyond the inner edges to engage the heads 37, and limit the upward movement of the floats 38 when the dock is sunk.

Each float 38 consists of an inner wall 4| and an outer wall 42, joined by radial partitions 43 having openings 44 with rim 45. At the inner walls 4|, each alternate partition i forked at 45, enclosing a triangular space 41-; and the wall 4! at spaces 41 has openings 48, atrequired points on the float, to connect these spaces to the at-- mosphere. At the lower ends of these spaces the bottoms of the cylinders also are open, as shown in Figure 11. The water can enter andflow through the spaces 46. 7

Attached to the web 49 of each base beam 35, onboth faces at the outer ends, are three stiffening plates 50, two of which are in line with both flanges 5| of the upright I-beams 33. The

headon these beams comprises a' top plate 52 with a circular rib 53 on its lower facein line with the outer flanges of the beams 36, and two transverse inverted T-beams 54, which rest on the tops of the colums 3B; the rib 53 resting on the lower flanges of beams 54. These beams 54 are welded together in pieces, web to web and flange to flange to make them fast; and the top 52 is afixed to the flanges of beams 54 at their upper edges. On the top of the plate 52 is a peripheral ring 55 bolted'thereon, and welded to this ring is a thick depending rim 56 with rounded exterior, a illustrated in Figure 9, enveloping the rib 53 and beams 54. stiffener plates 5'! are welded to the web of the. crossbeams 54 in line with the inner flanges of the beams 36.

Whenthe dock is sunk and a ship moved in between the walls 2, the ship, as the dock is raised again, will gradually settle' on the shockabsorbers 5. Since the members 38 are airtight, they "riseinj the water till checked by the stops ltflengaging the heads 52. When the bottom of the ship, indicated at S in Figure 11, makes contact. with the floats, it will press down on the gaskets 38, trapping water between it and the heads 52. This Water is expelled between the heads 52 and the inner walls 4| of the floats, and. some by way of openings 48 and spaces 4?. The diameter of the head 52 is smaller than the inside diameter of the walls 4! of the floats, and water can thus pass between them. Thus, any collisions between the floor of the hull I of the dock .and the bottom of the ship along the keel and bilge blocks are cushioned and damage averted. A side swing of the ship is taken up by .the shock-absorbing units 6 described above. In Figures 13 and 14, the base for the shockabsorber is made by attaching to the floor of the dock a pair of parallel runners in the shape of T-beams 59} On top of the flanges of these beams is an octagonal plate 60, welded into place; and on the upper face of .this plate are four reinforced angle irons 6!. These irons are bolted to the plate 60, with reinforcing plates 62 on the under face of the plate 63. Running between opposite angle irons 61 are crossed I- beams 63, pieced together and welded in place, with the upper faces flush throughout. Upon these beams the I-beams 36 are welded to make the pedestal for the head 38. At the side of beams 63 are stiffening plates 57 in'line with the inner flanges of beams 35. This type of base is well adapted for shock-absorbers under the keel of the ship.

For the sides of the dock, inthe line of the bilge blocks a base such as is shown in Figures l5, l6 and 17 is employed. Here the parallel runners 59 are spanned by three I-beams 65, secured by bolts 56 at their ends to the top faces of the Webs of the runners 59. Strengthening plates 62 are placed under said webs and are also held fast by the bolts 66. On topof the I-beams is a pair of T-beams 68, the tops of which are inclined at the correct angle for the uprights 36 and heads 3'! attached thereto to enable the floats to be parallel to the ship's bottom along the bilge blocks. stiffening plates 61 are attached to the webs and flanges of the beams 68 and 65 and the runners 59 wherever needed.

Figures 18 to 21 inclusive show an alternative form of base and pedestal for shock-absorber to engage the vessels keel. In this construction two parallel I-beams 59 are attached to the floor of the dock and on top of said beams is a plate 58 on which the columns 35 stand. The beams 69, plate 10 and columns 35 are all Welded together. The corners of the plate Hi and the outer corners of the top flange of the beams 69 are cut away as shown.

Both forms of shock-absorber thus include a piston member and a cylinder member, one of which is movable and tiltable with respect to the other. In the shock-absorbers on the side walls, the piston moves and tilts in its cylinder; and in the shock-absorbers for the deck or floor of the hull, the cylinder or float 38 is movable and can tilt with respect to the piston fixed to its upright pedestal in line with the central keel blocks, or inclined pedestal in line with the side bilge blocks. The rims of the pistons I and 52 are curved in the direction of the main axis to facilitate the tilting movement.

Having described my invention, what I believe to be new is:

1. A floating dry dock having a hull and a wall at each side of said hull, hydraulic;shockabsorbing units mounted on the inner faces of said walls, and hydraulic shock-absorbing units on the deck of said hull between said walls, each of said units comprising an open cylinder and a piston therein of a diameter small enough to permit water in the cylinder to flow past the piston.

.2. A floating dry dock having a hull with side walls thereon, said dock being equipped on the deck of the hull and the opposing inboard faces of said walls with shock absorbers, each of which comprises an automatically adjustable member to engage the outside of a ship in said dock squarely at Varying angles of impact, and a member loosely fitting said adjustable member to permit fluid to pass between saidmembers.

3. A floating dry dock having a hull and side walls, said dock being equipped on the deck of the hull and the opposing inboard faces of said walls with shock-absorbers, each comprising a cylinder and a piston one of which is movable and tiltable with respect to the other, the cylinder being open to be filled with water when the dock is sunk.

l. The dry dock according to claim 3 wherein the piston has a periphery curved in the direction of its main axis, and fits the cylinder loosely.

5. A floating dry dock having a hull and side walls thereon, and shock-absorbers on the opposing inboard faces of said walls and the deck of the hull between same, each of said shockabsorbers comprising an automatically adjustable member to engage the outside of a ship in said dock squarely at all angles of impact, and a member loosely fitting said adjustable member to permit fluid to pass between said members.

6. A floating dry dock comprising a hull and side walls thereon, and shock-absorbers on the inner faces of said walls and the deck of the dock between them, each shock-absorber including a cylinder and piston, one of which is movable and tiltable with respect to the other, the cylinder being open to be filled with water when the dock is submerged to receive a ship.

'7. The dry dock according to claim 6 wherein the piston has a rim curved in the direction of its main axis to facilitate tilting of the movable part, and fits loosely in said cylinder.

8. The dry dock according to claim 6 wherein the shock-absorbers on the side walls have the cylinders fixed and the pistons are movable with respect thereto; and the shock-absorbers on the hull deck have the pistons fixed and the cylinders movable thereon.

9. A floating dry dock having a hull and side walls, shock-absorbers mounted on the inner faces of said walls and the deck of said hull; each of said shock-absorbers comprising a cylinder and a piston, one of which is movable and tiltable with respect to the other, and bases "for said shock-absorbers, some of said bases being higher on one side than on the other to mount the shock-absorber at an incline to the surface supporting same.

10. A shock-absorber for a dry dock to engage the outside of a ship therein, comprising a cylinder member and a piston member, one of which is movable and tiltable with respect to the other, and fits the other loosely enough for the passage of fluid between the two, the movable member carrying a cushioning element, said piston having a rim which is curved in the direction of the main axis thereof, to facilitate the tilting of the movable member.

11. A shock-absorber for a dry dock to enage the bottom of a ship therein, said shockabsorber comprising a base on the deck of the dock, columns secured to the base, a piston affixed to the upper ends of said columns and an annular float loosely encircling the piston.

12. A shock-absorber for a. dry dock to engage the bottom of a vessel therein, said shockabsorber comprising a pedestal on the deck of the dock, a piston fixed to the top of the pedestal, and a hollow annular float loosely encircling said piston, said float having an inner and an outer wall connected by radial reinforcing partitions therein and. means forming longitudinal channels with openings at their 'lower ends and through said inner wall adjacent said piston.

13. A shock-absorber for a dry dock to engage the outside of a ship therein, said shockabsorber comprising a piston, a cylinder to receive the piston, an external cushioned head,

posts uniting said head and said piston, a transversely slidable closure plate for the cylinder, said plate having openings for said posts, and'compression springs between the plate and said head.

14. A shock-absorber for a floating dry dock to engage the outside of a ship therein, said shock-absorber comprising a cylinder having its inner end closed and its outer end open, a piston in the cylinder, a cushioned head outside of the cylinder, posts uniting said head to said piston, said cylinder having a rim surrounding its outer end, the rim. having radial ribs on its outer face, a closure plate engaging said ribs and having openings for said posts, rings on the posts abutting the plate to close the openings and springs encircling said posts abutting said head and said rings.

15. The shock-absorber according to claim 14 wherein said cylinder has reinforcing ribs along its sides and a base comprising cross beams to FREDERIC R. HARRIS. 

